MirOS Manual: chown(2), fchown(2), lchown(2)

CHOWN(2)                   BSD Programmer's Manual                    CHOWN(2)

NAME

     chown, lchown, fchown - change owner and group of a file or link

SYNOPSIS

     #include <sys/types.h>
     #include <unistd.h>

     int
     chown(const char *path, uid_t owner, gid_t group);

     int
     lchown(const char *path, uid_t owner, gid_t group);

     int
     fchown(int fd, uid_t owner, gid_t group);

DESCRIPTION

     The owner ID and group ID of the file (or link) named by path or refer-
     enced by fd is changed as specified by the arguments owner and group. The
     owner of a file may change the group to a group of which he or she is a
     member, but the change owner capability is restricted to the superuser.

     By default, chown() clears the set-user-ID and set-group-ID bits on the
     file to prevent accidental or mischievous creation of set-user-ID and
     set-group-ID programs. This behaviour can be overridden by setting the
     sysctl(8) variable fs.posix.setuid to zero.

     lchown() operates similarly to how chown() operated on older systems, and
     does not follow symbolic links. It allows the owner and group of a sym-
     bolic link to be set.

     fchown() is particularly useful when used in conjunction with the file
     locking primitives (see flock(2)).

     One of the owner or group IDs may be left unchanged by specifying it as
     -1.

RETURN VALUES

     Zero is returned if the operation was successful; -1 is returned if an
     error occurs, with a more specific error code being placed in the global
     variable errno.

ERRORS

     chown() or lchown() will fail and the file or link will be unchanged if:

     [ENOTDIR]     A component of the path prefix is not a directory.

     [ENAMETOOLONG]
                   A component of a pathname exceeded {NAME_MAX} characters,
                   or an entire path name exceeded {PATH_MAX} characters.

     [ENOENT]      The named file does not exist.

     [EACCES]      Search permission is denied for a component of the path
                   prefix.

     [ELOOP]       Too many symbolic links were encountered in translating the
                   pathname.

     [EPERM]       The effective user ID is not the superuser.

     [EROFS]       The named file resides on a read-only file system.

     [EFAULT]      path points outside the process's allocated address space.
     [EIO]         An I/O error occurred while reading from or writing to the
                   file system.

     fchown() will fail if:

     [EBADF]       fd does not refer to a valid descriptor.

     [EINVAL]      fd refers to a socket, not a file.

     [EPERM]       The effective user ID is not the superuser.

     [EROFS]       The named file resides on a read-only file system.

     [EIO]         An I/O error occurred while reading from or writing to the
                   file system.

SEE ALSO

     chgrp(1), chmod(2), flock(2), chown(8)

STANDARDS

     The chown() function is expected to conform to IEEE Std 1003.1-1988
     ("POSIX").

HISTORY

     The fchown() function call appeared in 4.2BSD.

     The chown() and fchown() functions were changed to follow symbolic links
     in 4.4BSD.

     The lchown() function was added to OpenBSD due to the above.

MirOS BSD #10-current          January 25, 1997                              1

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